Swab



- Dec. 11, 1934. E. v. CROWELL 1,983523 SWAB Filed June ll, 1929 BY y f*Mmm.

Patented Dec. 11, 1934 UNI-TED STATES PATENT OFFICE SWAB Erd V. Crowell,Los Angeles, Calif.

Application June 11, 1929, Serial No. 370,022

14 claims. (01.103-225) This invention is an improvement in that type ofswab disclosed for example in U. S. Patent No. 1,412,213 of April 1l,1922, wherein the iiuid pressure in a well bore by entering the mouth ofy,5 an upwardly opening cup-shaped swabbing element tends to yieldablyexpand the swab to operative engagement with the wall of the bore.

It is the object of the present invention to provide such a cup-shapedswabbing element having improved means for preventing its distortion ormutilation, while permitting its free radial contraction and expansionfor passage through a well bore and swabbing engagement with the wallthereof without excessive wear.

It is a further object of the invention to prevent distortion ormutilation of the swab by a protecting means adapted for cushioningengagement with the wall of the bore so as to eliminate al1 possibilityof contact such as might cause excessive wear.

20 It is a still further object of the invention to provide for extremesimplicity of manufacture, with the nished product comprising a durableand substantially integral structure having inherent strength adaptingit for the long and hard 25 usage to which swabs are normally subjected.

It is a still further object of the invention to provide a valvularmeans whereby the bore of the swab is positively opened for passage offluid by lowering the supporting element of the device with relation tothe swabbing element which is frictionally held by its engagement withthe wall of the bore, with said valvular means positively closed fortrapping the fluid above the same when the supporting element issubsequently elevated for withdrawing the swab.

Further objects of the invention will be readily understood fromA thefollowing description of the accoinponying drawing, in which:

Fig. 1 is a side elevation ofthe swab, partly in axial section andshowing the relative position of the parts as the swab is lowered in awell bore.

Fig. 2 is a similar view of one element of the swab, showing therelative position of the parts as the swab is withdrawn from the wellbore.

Figs. 3 and 4 are' transverse sections on the lines 3--3 and 4 4respectively of Fig` 1.

The swab is adapted for use in casing, tubing or other piping in thebore of a well, hereinafter referred to simply as the well bore, and maybe run in and withdrawn by suspending the same from drill-pipe, suckerrods, cr any other suitable drill string.

Any desired number of interchangeable swabbing elements may be connectedso as to form a swab of any desired length, the embodiment of theinvention illustrated at Fig. 1 showing two such swabbing elements, withtheir connecting mandrel broken away at the line A-A to indicate thepossibility of including additional swabbing elements.

The swabbing elements are respectively slidably mounted on mandrels 1which may be detachably connected by usual pin and box couplings 2 3,with the mandrel of the upper swabbing element having means forsuspending the swab from a suitable drill string, the said suspensionmeans shown in the present instance as a threaded pin 4 adapted to.engage a usual string of sucker rods (not shown). A bull plug 5 may besuspended from the mandrel of the lower swabbing element, for example bya threaded bore 3a adapted to receive pin end 2 of the lower mandrel.

The mandrels are preferably each provided with means for limiting upwardsliding of the corresponding swabbing element, the said means beingshown in the present instance as undercut annular shoulders 6 on therespective mandrels in spaced relation above their lower ends. Valveheads '7 carried by the mandrels preferably cooperate with valve seatsin the lower ends of the bores of the swabbing elements, one of saidvalves being preferably provided at the upper end of the box coupling 3of each of the intermediate mandrels, and one of said valves being alsoprovided at the upper end of bull plug 5, so that when a plurality ofmandrels l are operatively assembled as shown in Fig. 1, one of thevalves 7 will cooperate with the corresponding valve seat in the lowerend of the respective swabbing elements.

The swabbing elements are `interchangeably slidable on their respectivemandrels, and each comprises acup-shaped swabbing element 10 hav- `ing ahollow bore lladapted to loosely receive its corresponding mandrel, withthe lower end of bore 11 forming a valve seat 12 adapted for engagementby the corresponding Valve 7, and the upper end of said cup-shapedswabbing element having upwardly extending, axially projecting andcircumierentially spaced supporting ngers 13 terminating in a collar 14which is slidably received on the supporting mandrel. When the swab islowered in a well bore frictional engagement of the swabbing elementswith the wall of the bore will tend to hold the swabbing elements sothat the mandrels 1 may be lowered relative thereto for opening valves 7as shown in Fig. 1, and with the valves in open position the swabbingelements are then lowered in the well along with their mandrels as aresult of abutment of the swabbing elements against the correspondingannular shoulders 6. Fluid in the well thus passes through the bores ofthe swabbing elements and is discharged through the spaces formedbetween the circumferentially spaced protecting fingers 13; and when theswab is subsequently withdrawn from the well elevation of mandrels 1with relation to the frictionally held swabbing elements closes valves'7 as shown in Fig. 2, thereby trapping uid above thev swabbing elementsthrough the abutment or" the valves 7 against the lower ends of therespective swabbing elements.

During withdrawal of the swab the pressure of the trapped fluid on thecup-shaped upper ends of the swabbing elements tends to radially eX-pand said elements for fluid tight engagement with the wall of the wellbore, and the supporting 'lngers 13 which project upwardly from theswabbing elements prevent excessive distortion of the cup-shaped upperends of the swabbing elements, and also ward off any obstructions suchas might tend to mutilate or cause excessive wear of the swabbingelements. The supporting :lingers are of somewhat flexible, resilientmaterial so as to hold the cup-shaped swabbing elements against collapsewhile permitting sufficient yielding thereof for avoiding obstructionsor irregularities in the well bore, and the flexible fingers are alsoor" a suitable cushioning material adapted to readily yield withoutexcessive wear when meeting obstructions in the well bore.

As an instance of this arrangement the swabbing element 10 is preferablya hollow sleeve made of rubber of such consistency as to provide awear-resisting but readily yieldably peripheral contacting surface, andthe supporting fingers 13 which project upwardly from sleeve 10 arepreferably integral therewith and may be formed of the same rubber,which while readily yieldable is normally shape-retaining so that thefingers provide cushioning retaining means for the upper end of sleevev10. The collar 14 at the upper ends of 'lingers 13 is preferably alsointegral therewith and may be formed of the same rubber.

The peripheral wall of sleeve 10 is of appreciable thickness, and thebore of the sleeve preferably flares outwardly at its upper end as shownat 15, so as to form a cup-shaped structure terminating in a relativelysharp peripheral edge 16, and the fingers 13 project upwardly from therelatively thick peripheral wall of the cup, with the outer periphery ofthe fingers preferably forming an upwardly tapering continuation of theperipheral edge 16 and the inner periphery of the ngers merging intosurfacel between its inner and outer peripheries. The fingers `may thushave an appreciable radial thickness without projecting radiallyoutwardly beyond the peripheral edge 16 of the cup, with the side edgesof the fingers preferably curving to meet the peripheral edge 16 asshown in Fig. 1, so that the fingers are of sufcient rigidity to preventexcessive distortion of the mouth of the cup-shaped swabbing element,while permitting its free radial expansion responsive to pressure of uidthereon in order that the peripheral contact surface o1" sleeve 10 maymaintain a iiuid tight engagement with the wall or" the well bore. Asshown in Fig. 2, flaring the mouth 15 of the sleeve 10 and merging thecircumferentially spaced fingers 13 into the relatively thick peripheralwall of the sleeve, with the inner periphery of the ingers spacedradially outwardly from the inner periphery of said wall, annularlyrecesses and weakens the inner periphery of the wall of the cup-shapedsleeve adjacent its mouth; and as a consequence the cup-shaped sleeve isadapted for unito-rm operative expansion without excessive bulging atthe base of the cup where the weight of the ioad exerts the greatestexpansive force, since the lesser expansive force at the weakened mouthof the sleeve provides substantially the same radial expansion at themouth of the swabbing element as the greater expansive force at the baseof the cup.

A non-yieldable retaining collar 18 of metal or the like, is preferablyreceived on the lower end of sleeve l is of less diameter than that ofthe upper portion of the sleeve as shown in Fig. 1, so that only thatportion of the sleeve above the non-yieldable retaining collar providesa Contact surface adapted for engagement with the wall of the well bore.The lower end of collar 18 is preferably tapered as shown at 19, withthe end of sleeve l forming a continuation of said taper and the lowerend of the bore 1l of the sleeve oppositely tapering to form the valveseat l2. The collar 13 is securely fixed with relation to sleeve 10, andfor this purpose may be provided with radial openings 20 and with aninterior shoulder 21 adapted to engage and hold the rubber of which thesleeve is formed.

A guide for mandrel 1 is preferably provided in the bore of sleeveadjacent its lower end, and may form stops adapted for engagement by theshouider 6 of the mandrel for limiting relative axial movement of theswabbing element. For this purpose a bushing 23 having inwardlyprojecting, circumierentially spaced radial lugs 24 is preferablymounted in bore l1 between the shoulder 6 of the mandrel and they valveseat l2, with said lugs deining a central bore for passage of themandrel so as to center the same with relation to sleeve 10, but adaptedfor abutment against shoulder 6 as shown in Fig. 2 in order to limitrelative axial movement of the swabbing element. The bushing 23 may beheld in place by threading its outer perhipery as shown at 25, so thatthe rubber of which sleeve 10 is formed will seat in the grooves of thethreads.

rihe swabbing element as thus described may be formed in a suitablemold. For this purpose the collar 18 and bushing 23 are placed in a moldwhich is` adapted to denne the exterior contour of the swabbing element,and a suitable core which is adapted to form the bore of the swabbingelement and its spaced supporting ngers 13 and collar 14, is also placedin the mold. 'Ihe spaces between the lugs 24 of bushing 23 may be lledwith molding sand. The prepared mold is then filled with plastic rubberwhich is suitably vulcanized so that the rubber is securely molded tobushing 23 and to collar 18, and by then stripping the molded articlefrom its mold and removing the sand from between the lugs 24, asubstantially integral swabbing element is formed which provides ayieldable cup-shaped swab having supporting lingers for preventingdistortion 0r mutilation oi the cup, with said fingers formed of acushioning material adapted to readily yield when meeting anobstruction.

1 claim: I,

l. In a swab, an integral molded' structure of resiliently iieXiblecushioning material comprising a cup with supporting ngers projectingupwardly therefrom and a collar of the same material connecting theupper ends of the supporting lingers.

2. A swabbing element comprising flexible material molded to form asleeve having one end embedded in a retaining annulus and its oppositeend forming a cup having supporting ngers projecting upwardly therefromin circumferentially spaced relation and terminating in a collar ofreduced diameter.

3. In a swab, a swabbing element comprising flexible material molded toform a hollow sleeve having one end embedded in a retaining annulus witha bushing having inwardly projecting circumferentially spaced guide lugsembedded in the bore of said end of the sleeve, the opposite end of themolded sleeve forming a cup having supporting iingers projectingupwardly therefrom in circumferentially spaced relation and terminatingin a collar of reduced diameter, and a mandrel in the bore of the sleevecentered in the bushing by the guide lugs.

4. In a swab, an integral structure of flexible material comprising acup with supporting fingers projecting upwardly therefrom andterminating in an annular collar.

5. In a swab, an integral structure of flexible material comprising acup with supporting ngers projecting upwardly from the outer peripheralportion of the cup in circumferentially spaced relation and terminatingin an annular collar.

6. In a swab, an integral structure of flexible material comprising acup with supporting ngers projecting upwardly from the outer peripheralportion of the cup in circumferentially spaced relation and convergentlyinclined toward their upper ends and terminating in an annular collar.

7. In a swab, an integral structure of flexible material comprising acup with supporting ngers projecting upwardly from the outer peripheralportion of the cup in circumierentially spaced relation with the sidesof next adjacent fingers curving to meet the outer periphery of the cupand the fingers terminating in an annular collar.

8. In a swab, an integral structure of flexible material having a hollowbore and comprising a cup with supporting lingers projecting upwardlytherefrom and terminating in an annular collar, guide lugs projectinginto the hollow bore, and a supporting mandrel centered in the hollowbore by the guide lugs.

9. In a swab, an integral structure of flexible material comprising acup with supporting 1ingers projecting upwardly therefrom andterminating in an annular collar, the integral structure having an openbore, and a valve seat at the lower end of the open bore.

10. In a swab, an integral structure of flexible material comprising acup with supporting iingers projecting upwardly therefrom and terminating in an annular collar, the integral structure having an open bore,and the flexible material forming a cushioning Valve seat at the lowerend of the bore.

11. In a swab, an integral molded structure comprising a cup withsupporting ngers projecting upwardly therefrom and terminating in anannular collar, and an annulus recessed to receive the molded structurefor securing the annulus relative to the molded structure.

12. In a swab, an integral structure of iiexible material comprising acup with supporting fingers projecting upwardly therefrom andterminating in an annular collar, the cup being adapted for expansion bypressure exerted downwardly into the cup, and the cup beingsubstantially weakened below the lingers and adjacent its mouth.

13. In a swab, an integral structure of flexible material comprising acup with supporting ngers projecting upwardly therefrom and terminatingin an annular collar, the cup being adapted for expansion by pressureexerted downwardly into the cup, and the cup being annularly recessedbelow the ngers and adjacent its mouth.

14. In a swab, an integral structure of iiexible material comprising acup having a peripheral wall of appreciable thickness and fingersprojecting upwardly from said peripheral wall, the peripheral wall beingtapered at its upper end so as to form a flaring mouth for the cup, andthe fingers being of appreciable radial thickness but having their innerperiphery spaced radially outwardly from the inner periphery of saidilaring mouth and their outer periphery forming a continuation of theouter periphery of said mouth.

ERD V. CROWELL.

